ovsdb/jsonrpc-server.c

   1 /* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014, 2015 Nicira, Inc.
   2  *
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15
  16 #include <config.h>
  17
  18 #include "jsonrpc-server.h"
  19
  20 #include <errno.h>
  21
  22 #include "bitmap.h"
  23 #include "column.h"
  24 #include "dynamic-string.h"
  25 #include "monitor.h"
  26 #include "json.h"
  27 #include "jsonrpc.h"
  28 #include "ovsdb-error.h"
  29 #include "ovsdb-parser.h"
  30 #include "ovsdb.h"
  31 #include "poll-loop.h"
  32 #include "reconnect.h"
  33 #include "row.h"
  34 #include "server.h"
  35 #include "simap.h"
  36 #include "stream.h"
  37 #include "table.h"
  38 #include "timeval.h"
  39 #include "transaction.h"
  40 #include "trigger.h"
  41 #include "openvswitch/vlog.h"
  42
  43 VLOG_DEFINE_THIS_MODULE(ovsdb_jsonrpc_server);
  44
  45 struct ovsdb_jsonrpc_remote;
  46 struct ovsdb_jsonrpc_session;
  47
  48 /* Set false to defeature monitor2, causing jsonrpc to respond to monitor2
  49  * method with an error.  */
  50 static bool monitor2_enable__ = true;
  51
  52 /* Message rate-limiting. */
  53 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
  54
  55 /* Sessions. */
  56 static struct ovsdb_jsonrpc_session *ovsdb_jsonrpc_session_create(
  57     struct ovsdb_jsonrpc_remote *, struct jsonrpc_session *);
  58 static void ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *);
  59 static void ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *);
  60 static void ovsdb_jsonrpc_session_get_memory_usage_all(
  61     const struct ovsdb_jsonrpc_remote *, struct simap *usage);
  62 static void ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *);
  63 static void ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *);
  64 static void ovsdb_jsonrpc_session_set_all_options(
  65     struct ovsdb_jsonrpc_remote *, const struct ovsdb_jsonrpc_options *);
  66 static bool ovsdb_jsonrpc_session_get_status(
  67     const struct ovsdb_jsonrpc_remote *,
  68     struct ovsdb_jsonrpc_remote_status *);
  69 static void ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *);
  70 static void ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *);
  71 static void ovsdb_jsonrpc_session_send(struct ovsdb_jsonrpc_session *,
  72                                        struct jsonrpc_msg *);
  73
  74 /* Triggers. */
  75 static void ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *,
  76                                          struct ovsdb *,
  77                                          struct json *id, struct json *params);
  78 static struct ovsdb_jsonrpc_trigger *ovsdb_jsonrpc_trigger_find(
  79     struct ovsdb_jsonrpc_session *, const struct json *id, size_t hash);
  80 static void ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *);
  81 static void ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *);
  82 static void ovsdb_jsonrpc_trigger_complete_done(
  83     struct ovsdb_jsonrpc_session *);
  84
  85 /* Monitors. */
  86 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_create(
  87     struct ovsdb_jsonrpc_session *, struct ovsdb *, struct json *params,
  88     enum ovsdb_monitor_version, const struct json *request_id);
  89 static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_cancel(
  90     struct ovsdb_jsonrpc_session *,
  91     struct json_array *params,
  92     const struct json *request_id);
  93 static void ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *);
  94 static void ovsdb_jsonrpc_monitor_flush_all(struct ovsdb_jsonrpc_session *);
  95 static bool ovsdb_jsonrpc_monitor_needs_flush(struct ovsdb_jsonrpc_session *);
  96 static struct json *ovsdb_jsonrpc_monitor_compose_update(
  97     struct ovsdb_jsonrpc_monitor *monitor, bool initial);
  98
  99 \f
 100 /* JSON-RPC database server. */
 101
 102 struct ovsdb_jsonrpc_server {
 103     struct ovsdb_server up;
 104     unsigned int n_sessions, max_sessions;
 105     struct shash remotes;      /* Contains "struct ovsdb_jsonrpc_remote *"s. */
 106 };
 107
 108 /* A configured remote.  This is either a passive stream listener plus a list
 109  * of the currently connected sessions, or a list of exactly one active
 110  * session. */
 111 struct ovsdb_jsonrpc_remote {
 112     struct ovsdb_jsonrpc_server *server;
 113     struct pstream *listener;   /* Listener, if passive. */
 114     struct ovs_list sessions;   /* List of "struct ovsdb_jsonrpc_session"s. */
 115     uint8_t dscp;
 116 };
 117
 118 static struct ovsdb_jsonrpc_remote *ovsdb_jsonrpc_server_add_remote(
 119     struct ovsdb_jsonrpc_server *, const char *name,
 120     const struct ovsdb_jsonrpc_options *options
 121 );
 122 static void ovsdb_jsonrpc_server_del_remote(struct shash_node *);
 123
 124 /* Creates and returns a new server to provide JSON-RPC access to an OVSDB.
 125  *
 126  * The caller must call ovsdb_jsonrpc_server_add_db() for each database to
 127  * which 'server' should provide access. */
 128 struct ovsdb_jsonrpc_server *
 129 ovsdb_jsonrpc_server_create(void)
 130 {
 131     struct ovsdb_jsonrpc_server *server = xzalloc(sizeof *server);
 132     ovsdb_server_init(&server->up);
 133     server->max_sessions = 330;   /* Random limit. */
 134     shash_init(&server->remotes);
 135     return server;
 136 }
 137
 138 /* Adds 'db' to the set of databases served out by 'svr'.  Returns true if
 139  * successful, false if 'db''s name is the same as some database already in
 140  * 'server'. */
 141 bool
 142 ovsdb_jsonrpc_server_add_db(struct ovsdb_jsonrpc_server *svr, struct ovsdb *db)
 143 {
 144     /* The OVSDB protocol doesn't have a way to notify a client that a
 145      * database has been added.  If some client tried to use the database
 146      * that we're adding and failed, then forcing it to reconnect seems like
 147      * a reasonable way to make it try again.
 148      *
 149      * If this is too big of a hammer in practice, we could be more selective,
 150      * e.g. disconnect only connections that actually tried to use a database
 151      * with 'db''s name. */
 152     ovsdb_jsonrpc_server_reconnect(svr);
 153
 154     return ovsdb_server_add_db(&svr->up, db);
 155 }
 156
 157 /* Removes 'db' from the set of databases served out by 'svr'.  Returns
 158  * true if successful, false if there is no database associated with 'db'. */
 159 bool
 160 ovsdb_jsonrpc_server_remove_db(struct ovsdb_jsonrpc_server *svr,
 161                                struct ovsdb *db)
 162 {
 163     /* There might be pointers to 'db' from 'svr', such as monitors or
 164      * outstanding transactions.  Disconnect all JSON-RPC connections to avoid
 165      * accesses to freed memory.
 166      *
 167      * If this is too big of a hammer in practice, we could be more selective,
 168      * e.g. disconnect only connections that actually reference 'db'. */
 169     ovsdb_jsonrpc_server_reconnect(svr);
 170
 171     return ovsdb_server_remove_db(&svr->up, db);
 172 }
 173
 174 void
 175 ovsdb_jsonrpc_server_destroy(struct ovsdb_jsonrpc_server *svr)
 176 {
 177     struct shash_node *node, *next;
 178
 179     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 180         ovsdb_jsonrpc_server_del_remote(node);
 181     }
 182     shash_destroy(&svr->remotes);
 183     ovsdb_server_destroy(&svr->up);
 184     free(svr);
 185 }
 186
 187 struct ovsdb_jsonrpc_options *
 188 ovsdb_jsonrpc_default_options(const char *target)
 189 {
 190     struct ovsdb_jsonrpc_options *options = xzalloc(sizeof *options);
 191     options->max_backoff = RECONNECT_DEFAULT_MAX_BACKOFF;
 192     options->probe_interval = (stream_or_pstream_needs_probes(target)
 193                                ? RECONNECT_DEFAULT_PROBE_INTERVAL
 194                                : 0);
 195     return options;
 196 }
 197
 198 /* Sets 'svr''s current set of remotes to the names in 'new_remotes', with
 199  * options in the struct ovsdb_jsonrpc_options supplied as the data values.
 200  *
 201  * A remote is an active or passive stream connection method, e.g. "pssl:" or
 202  * "tcp:1.2.3.4". */
 203 void
 204 ovsdb_jsonrpc_server_set_remotes(struct ovsdb_jsonrpc_server *svr,
 205                                  const struct shash *new_remotes)
 206 {
 207     struct shash_node *node, *next;
 208
 209     SHASH_FOR_EACH_SAFE (node, next, &svr->remotes) {
 210         struct ovsdb_jsonrpc_remote *remote = node->data;
 211         struct ovsdb_jsonrpc_options *options
 212             = shash_find_data(new_remotes, node->name);
 213
 214         if (!options) {
 215             VLOG_INFO("%s: remote deconfigured", node->name);
 216             ovsdb_jsonrpc_server_del_remote(node);
 217         } else if (options->dscp != remote->dscp) {
 218             ovsdb_jsonrpc_server_del_remote(node);
 219          }
 220     }
 221     SHASH_FOR_EACH (node, new_remotes) {
 222         const struct ovsdb_jsonrpc_options *options = node->data;
 223         struct ovsdb_jsonrpc_remote *remote;
 224
 225         remote = shash_find_data(&svr->remotes, node->name);
 226         if (!remote) {
 227             remote = ovsdb_jsonrpc_server_add_remote(svr, node->name, options);
 228             if (!remote) {
 229                 continue;
 230             }
 231         }
 232
 233         ovsdb_jsonrpc_session_set_all_options(remote, options);
 234     }
 235 }
 236
 237 static struct ovsdb_jsonrpc_remote *
 238 ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *svr,
 239                                 const char *name,
 240                                 const struct ovsdb_jsonrpc_options *options)
 241 {
 242     struct ovsdb_jsonrpc_remote *remote;
 243     struct pstream *listener;
 244     int error;
 245
 246     error = jsonrpc_pstream_open(name, &listener, options->dscp);
 247     if (error && error != EAFNOSUPPORT) {
 248         VLOG_ERR_RL(&rl, "%s: listen failed: %s", name, ovs_strerror(error));
 249         return NULL;
 250     }
 251
 252     remote = xmalloc(sizeof *remote);
 253     remote->server = svr;
 254     remote->listener = listener;
 255     list_init(&remote->sessions);
 256     remote->dscp = options->dscp;
 257     shash_add(&svr->remotes, name, remote);
 258
 259     if (!listener) {
 260         ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name, true));
 261     }
 262     return remote;
 263 }
 264
 265 static void
 266 ovsdb_jsonrpc_server_del_remote(struct shash_node *node)
 267 {
 268     struct ovsdb_jsonrpc_remote *remote = node->data;
 269
 270     ovsdb_jsonrpc_session_close_all(remote);
 271     pstream_close(remote->listener);
 272     shash_delete(&remote->server->remotes, node);
 273     free(remote);
 274 }
 275
 276 /* Stores status information for the remote named 'target', which should have
 277  * been configured on 'svr' with a call to ovsdb_jsonrpc_server_set_remotes(),
 278  * into '*status'.  On success returns true, on failure (if 'svr' doesn't have
 279  * a remote named 'target' or if that remote is an inbound remote that has no
 280  * active connections) returns false.  On failure, 'status' will be zeroed.
 281  */
 282 bool
 283 ovsdb_jsonrpc_server_get_remote_status(
 284     const struct ovsdb_jsonrpc_server *svr, const char *target,
 285     struct ovsdb_jsonrpc_remote_status *status)
 286 {
 287     const struct ovsdb_jsonrpc_remote *remote;
 288
 289     memset(status, 0, sizeof *status);
 290
 291     remote = shash_find_data(&svr->remotes, target);
 292     return remote && ovsdb_jsonrpc_session_get_status(remote, status);
 293 }
 294
 295 void
 296 ovsdb_jsonrpc_server_free_remote_status(
 297     struct ovsdb_jsonrpc_remote_status *status)
 298 {
 299     free(status->locks_held);
 300     free(status->locks_waiting);
 301     free(status->locks_lost);
 302 }
 303
 304 /* Forces all of the JSON-RPC sessions managed by 'svr' to disconnect and
 305  * reconnect. */
 306 void
 307 ovsdb_jsonrpc_server_reconnect(struct ovsdb_jsonrpc_server *svr)
 308 {
 309     struct shash_node *node;
 310
 311     SHASH_FOR_EACH (node, &svr->remotes) {
 312         struct ovsdb_jsonrpc_remote *remote = node->data;
 313
 314         ovsdb_jsonrpc_session_reconnect_all(remote);
 315     }
 316 }
 317
 318 void
 319 ovsdb_jsonrpc_server_run(struct ovsdb_jsonrpc_server *svr)
 320 {
 321     struct shash_node *node;
 322
 323     SHASH_FOR_EACH (node, &svr->remotes) {
 324         struct ovsdb_jsonrpc_remote *remote = node->data;
 325
 326         if (remote->listener) {
 327             if (svr->n_sessions < svr->max_sessions) {
 328                 struct stream *stream;
 329                 int error;
 330
 331                 error = pstream_accept(remote->listener, &stream);
 332                 if (!error) {
 333                     struct jsonrpc_session *js;
 334                     js = jsonrpc_session_open_unreliably(jsonrpc_open(stream),
 335                                                          remote->dscp);
 336                     ovsdb_jsonrpc_session_create(remote, js);
 337                 } else if (error != EAGAIN) {
 338                     VLOG_WARN_RL(&rl, "%s: accept failed: %s",
 339                                  pstream_get_name(remote->listener),
 340                                  ovs_strerror(error));
 341                 }
 342             } else {
 343                 VLOG_WARN_RL(&rl, "%s: connection exceeded maximum (%d)",
 344                              pstream_get_name(remote->listener),
 345                              svr->max_sessions);
 346             }
 347         }
 348
 349         ovsdb_jsonrpc_session_run_all(remote);
 350     }
 351 }
 352
 353 void
 354 ovsdb_jsonrpc_server_wait(struct ovsdb_jsonrpc_server *svr)
 355 {
 356     struct shash_node *node;
 357
 358     SHASH_FOR_EACH (node, &svr->remotes) {
 359         struct ovsdb_jsonrpc_remote *remote = node->data;
 360
 361         if (remote->listener && svr->n_sessions < svr->max_sessions) {
 362             pstream_wait(remote->listener);
 363         }
 364
 365         ovsdb_jsonrpc_session_wait_all(remote);
 366     }
 367 }
 368
 369 /* Adds some memory usage statistics for 'svr' into 'usage', for use with
 370  * memory_report(). */
 371 void
 372 ovsdb_jsonrpc_server_get_memory_usage(const struct ovsdb_jsonrpc_server *svr,
 373                                       struct simap *usage)
 374 {
 375     struct shash_node *node;
 376
 377     simap_increase(usage, "sessions", svr->n_sessions);
 378     SHASH_FOR_EACH (node, &svr->remotes) {
 379         struct ovsdb_jsonrpc_remote *remote = node->data;
 380
 381         ovsdb_jsonrpc_session_get_memory_usage_all(remote, usage);
 382     }
 383 }
 384 \f
 385 /* JSON-RPC database server session. */
 386
 387 struct ovsdb_jsonrpc_session {
 388     struct ovs_list node;       /* Element in remote's sessions list. */
 389     struct ovsdb_session up;
 390     struct ovsdb_jsonrpc_remote *remote;
 391
 392     /* Triggers. */
 393     struct hmap triggers;       /* Hmap of "struct ovsdb_jsonrpc_trigger"s. */
 394
 395     /* Monitors. */
 396     struct hmap monitors;       /* Hmap of "struct ovsdb_jsonrpc_monitor"s. */
 397
 398     /* Network connectivity. */
 399     struct jsonrpc_session *js;  /* JSON-RPC session. */
 400     unsigned int js_seqno;       /* Last jsonrpc_session_get_seqno() value. */
 401 };
 402
 403 static void ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *);
 404 static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *);
 405 static void ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *);
 406 static void ovsdb_jsonrpc_session_get_memory_usage(
 407     const struct ovsdb_jsonrpc_session *, struct simap *usage);
 408 static void ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *,
 409                                              struct jsonrpc_msg *);
 410 static void ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *,
 411                                              struct jsonrpc_msg *);
 412
 413 static struct ovsdb_jsonrpc_session *
 414 ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_remote *remote,
 415                              struct jsonrpc_session *js)
 416 {
 417     struct ovsdb_jsonrpc_session *s;
 418
 419     s = xzalloc(sizeof *s);
 420     ovsdb_session_init(&s->up, &remote->server->up);
 421     s->remote = remote;
 422     list_push_back(&remote->sessions, &s->node);
 423     hmap_init(&s->triggers);
 424     hmap_init(&s->monitors);
 425     s->js = js;
 426     s->js_seqno = jsonrpc_session_get_seqno(js);
 427
 428     remote->server->n_sessions++;
 429
 430     return s;
 431 }
 432
 433 static void
 434 ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s)
 435 {
 436     ovsdb_jsonrpc_monitor_remove_all(s);
 437     ovsdb_jsonrpc_session_unlock_all(s);
 438     ovsdb_jsonrpc_trigger_complete_all(s);
 439
 440     hmap_destroy(&s->monitors);
 441     hmap_destroy(&s->triggers);
 442
 443     jsonrpc_session_close(s->js);
 444     list_remove(&s->node);
 445     s->remote->server->n_sessions--;
 446     ovsdb_session_destroy(&s->up);
 447     free(s);
 448 }
 449
 450 static int
 451 ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s)
 452 {
 453     jsonrpc_session_run(s->js);
 454     if (s->js_seqno != jsonrpc_session_get_seqno(s->js)) {
 455         s->js_seqno = jsonrpc_session_get_seqno(s->js);
 456         ovsdb_jsonrpc_trigger_complete_all(s);
 457         ovsdb_jsonrpc_monitor_remove_all(s);
 458         ovsdb_jsonrpc_session_unlock_all(s);
 459     }
 460
 461     ovsdb_jsonrpc_trigger_complete_done(s);
 462
 463     if (!jsonrpc_session_get_backlog(s->js)) {
 464         struct jsonrpc_msg *msg;
 465
 466         ovsdb_jsonrpc_monitor_flush_all(s);
 467
 468         msg = jsonrpc_session_recv(s->js);
 469         if (msg) {
 470             if (msg->type == JSONRPC_REQUEST) {
 471                 ovsdb_jsonrpc_session_got_request(s, msg);
 472             } else if (msg->type == JSONRPC_NOTIFY) {
 473                 ovsdb_jsonrpc_session_got_notify(s, msg);
 474             } else {
 475                 VLOG_WARN("%s: received unexpected %s message",
 476                           jsonrpc_session_get_name(s->js),
 477                           jsonrpc_msg_type_to_string(msg->type));
 478                 jsonrpc_session_force_reconnect(s->js);
 479                 jsonrpc_msg_destroy(msg);
 480             }
 481         }
 482     }
 483     return jsonrpc_session_is_alive(s->js) ? 0 : ETIMEDOUT;
 484 }
 485
 486 static void
 487 ovsdb_jsonrpc_session_set_options(struct ovsdb_jsonrpc_session *session,
 488                                   const struct ovsdb_jsonrpc_options *options)
 489 {
 490     jsonrpc_session_set_max_backoff(session->js, options->max_backoff);
 491     jsonrpc_session_set_probe_interval(session->js, options->probe_interval);
 492     jsonrpc_session_set_dscp(session->js, options->dscp);
 493 }
 494
 495 static void
 496 ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *remote)
 497 {
 498     struct ovsdb_jsonrpc_session *s, *next;
 499
 500     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 501         int error = ovsdb_jsonrpc_session_run(s);
 502         if (error) {
 503             ovsdb_jsonrpc_session_close(s);
 504         }
 505     }
 506 }
 507
 508 static void
 509 ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *s)
 510 {
 511     jsonrpc_session_wait(s->js);
 512     if (!jsonrpc_session_get_backlog(s->js)) {
 513         if (ovsdb_jsonrpc_monitor_needs_flush(s)) {
 514             poll_immediate_wake();
 515         } else {
 516             jsonrpc_session_recv_wait(s->js);
 517         }
 518     }
 519 }
 520
 521 static void
 522 ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *remote)
 523 {
 524     struct ovsdb_jsonrpc_session *s;
 525
 526     LIST_FOR_EACH (s, node, &remote->sessions) {
 527         ovsdb_jsonrpc_session_wait(s);
 528     }
 529 }
 530
 531 static void
 532 ovsdb_jsonrpc_session_get_memory_usage(const struct ovsdb_jsonrpc_session *s,
 533                                        struct simap *usage)
 534 {
 535     simap_increase(usage, "triggers", hmap_count(&s->triggers));
 536     simap_increase(usage, "backlog", jsonrpc_session_get_backlog(s->js));
 537 }
 538
 539 static void
 540 ovsdb_jsonrpc_session_get_memory_usage_all(
 541     const struct ovsdb_jsonrpc_remote *remote,
 542     struct simap *usage)
 543 {
 544     struct ovsdb_jsonrpc_session *s;
 545
 546     LIST_FOR_EACH (s, node, &remote->sessions) {
 547         ovsdb_jsonrpc_session_get_memory_usage(s, usage);
 548     }
 549 }
 550
 551 static void
 552 ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *remote)
 553 {
 554     struct ovsdb_jsonrpc_session *s, *next;
 555
 556     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 557         ovsdb_jsonrpc_session_close(s);
 558     }
 559 }
 560
 561 /* Forces all of the JSON-RPC sessions managed by 'remote' to disconnect and
 562  * reconnect. */
 563 static void
 564 ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *remote)
 565 {
 566     struct ovsdb_jsonrpc_session *s, *next;
 567
 568     LIST_FOR_EACH_SAFE (s, next, node, &remote->sessions) {
 569         jsonrpc_session_force_reconnect(s->js);
 570         if (!jsonrpc_session_is_alive(s->js)) {
 571             ovsdb_jsonrpc_session_close(s);
 572         }
 573     }
 574 }
 575
 576 /* Sets the options for all of the JSON-RPC sessions managed by 'remote' to
 577  * 'options'.
 578  *
 579  * (The dscp value can't be changed directly; the caller must instead close and
 580  * re-open the session.) */
 581 static void
 582 ovsdb_jsonrpc_session_set_all_options(
 583     struct ovsdb_jsonrpc_remote *remote,
 584     const struct ovsdb_jsonrpc_options *options)
 585 {
 586     struct ovsdb_jsonrpc_session *s;
 587
 588     LIST_FOR_EACH (s, node, &remote->sessions) {
 589         ovsdb_jsonrpc_session_set_options(s, options);
 590     }
 591 }
 592
 593 static bool
 594 ovsdb_jsonrpc_session_get_status(const struct ovsdb_jsonrpc_remote *remote,
 595                                  struct ovsdb_jsonrpc_remote_status *status)
 596 {
 597     const struct ovsdb_jsonrpc_session *s;
 598     const struct jsonrpc_session *js;
 599     struct ovsdb_lock_waiter *waiter;
 600     struct reconnect_stats rstats;
 601     struct ds locks_held, locks_waiting, locks_lost;
 602
 603     status->bound_port = (remote->listener
 604                           ? pstream_get_bound_port(remote->listener)
 605                           : htons(0));
 606
 607     if (list_is_empty(&remote->sessions)) {
 608         return false;
 609     }
 610     s = CONTAINER_OF(remote->sessions.next, struct ovsdb_jsonrpc_session, node);
 611     js = s->js;
 612
 613     status->is_connected = jsonrpc_session_is_connected(js);
 614     status->last_error = jsonrpc_session_get_status(js);
 615
 616     jsonrpc_session_get_reconnect_stats(js, &rstats);
 617     status->state = rstats.state;
 618     status->sec_since_connect = rstats.msec_since_connect == UINT_MAX
 619         ? UINT_MAX : rstats.msec_since_connect / 1000;
 620     status->sec_since_disconnect = rstats.msec_since_disconnect == UINT_MAX
 621         ? UINT_MAX : rstats.msec_since_disconnect / 1000;
 622
 623     ds_init(&locks_held);
 624     ds_init(&locks_waiting);
 625     ds_init(&locks_lost);
 626     HMAP_FOR_EACH (waiter, session_node, &s->up.waiters) {
 627         struct ds *string;
 628
 629         string = (ovsdb_lock_waiter_is_owner(waiter) ? &locks_held
 630                   : waiter->mode == OVSDB_LOCK_WAIT ? &locks_waiting
 631                   : &locks_lost);
 632         if (string->length) {
 633             ds_put_char(string, ' ');
 634         }
 635         ds_put_cstr(string, waiter->lock_name);
 636     }
 637     status->locks_held = ds_steal_cstr(&locks_held);
 638     status->locks_waiting = ds_steal_cstr(&locks_waiting);
 639     status->locks_lost = ds_steal_cstr(&locks_lost);
 640
 641     status->n_connections = list_size(&remote->sessions);
 642
 643     return true;
 644 }
 645
 646 /* Examines 'request' to determine the database to which it relates, and then
 647  * searches 's' to find that database:
 648  *
 649  *    - If successful, returns the database and sets '*replyp' to NULL.
 650  *
 651  *    - If no such database exists, returns NULL and sets '*replyp' to an
 652  *      appropriate JSON-RPC error reply, owned by the caller. */
 653 static struct ovsdb *
 654 ovsdb_jsonrpc_lookup_db(const struct ovsdb_jsonrpc_session *s,
 655                         const struct jsonrpc_msg *request,
 656                         struct jsonrpc_msg **replyp)
 657 {
 658     struct json_array *params;
 659     struct ovsdb_error *error;
 660     const char *db_name;
 661     struct ovsdb *db;
 662
 663     params = json_array(request->params);
 664     if (!params->n || params->elems[0]->type != JSON_STRING) {
 665         error = ovsdb_syntax_error(
 666             request->params, NULL,
 667             "%s request params must begin with <db-name>", request->method);
 668         goto error;
 669     }
 670
 671     db_name = params->elems[0]->u.string;
 672     db = shash_find_data(&s->up.server->dbs, db_name);
 673     if (!db) {
 674         error = ovsdb_syntax_error(
 675             request->params, "unknown database",
 676             "%s request specifies unknown database %s",
 677             request->method, db_name);
 678         goto error;
 679     }
 680
 681     *replyp = NULL;
 682     return db;
 683
 684 error:
 685     *replyp = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 686     ovsdb_error_destroy(error);
 687     return NULL;
 688 }
 689
 690 static struct ovsdb_error *
 691 ovsdb_jsonrpc_session_parse_lock_name(const struct jsonrpc_msg *request,
 692                                       const char **lock_namep)
 693 {
 694     const struct json_array *params;
 695
 696     params = json_array(request->params);
 697     if (params->n != 1 || params->elems[0]->type != JSON_STRING ||
 698         !ovsdb_parser_is_id(json_string(params->elems[0]))) {
 699         *lock_namep = NULL;
 700         return ovsdb_syntax_error(request->params, NULL,
 701                                   "%s request params must be <id>",
 702                                   request->method);
 703     }
 704
 705     *lock_namep = json_string(params->elems[0]);
 706     return NULL;
 707 }
 708
 709 static void
 710 ovsdb_jsonrpc_session_notify(struct ovsdb_session *session,
 711                              const char *lock_name,
 712                              const char *method)
 713 {
 714     struct ovsdb_jsonrpc_session *s;
 715     struct json *params;
 716
 717     s = CONTAINER_OF(session, struct ovsdb_jsonrpc_session, up);
 718     params = json_array_create_1(json_string_create(lock_name));
 719     ovsdb_jsonrpc_session_send(s, jsonrpc_create_notify(method, params));
 720 }
 721
 722 static struct jsonrpc_msg *
 723 ovsdb_jsonrpc_session_lock(struct ovsdb_jsonrpc_session *s,
 724                            struct jsonrpc_msg *request,
 725                            enum ovsdb_lock_mode mode)
 726 {
 727     struct ovsdb_lock_waiter *waiter;
 728     struct jsonrpc_msg *reply;
 729     struct ovsdb_error *error;
 730     struct ovsdb_session *victim;
 731     const char *lock_name;
 732     struct json *result;
 733
 734     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 735     if (error) {
 736         goto error;
 737     }
 738
 739     /* Report error if this session has issued a "lock" or "steal" without a
 740      * matching "unlock" for this lock. */
 741     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 742     if (waiter) {
 743         error = ovsdb_syntax_error(
 744             request->params, NULL,
 745             "must issue \"unlock\" before new \"%s\"", request->method);
 746         goto error;
 747     }
 748
 749     /* Get the lock, add us as a waiter. */
 750     waiter = ovsdb_server_lock(&s->remote->server->up, &s->up, lock_name, mode,
 751                                &victim);
 752     if (victim) {
 753         ovsdb_jsonrpc_session_notify(victim, lock_name, "stolen");
 754     }
 755
 756     result = json_object_create();
 757     json_object_put(result, "locked",
 758                     json_boolean_create(ovsdb_lock_waiter_is_owner(waiter)));
 759
 760     return jsonrpc_create_reply(result, request->id);
 761
 762 error:
 763     reply = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 764     ovsdb_error_destroy(error);
 765     return reply;
 766 }
 767
 768 static void
 769 ovsdb_jsonrpc_session_unlock_all(struct ovsdb_jsonrpc_session *s)
 770 {
 771     struct ovsdb_lock_waiter *waiter, *next;
 772
 773     HMAP_FOR_EACH_SAFE (waiter, next, session_node, &s->up.waiters) {
 774         ovsdb_jsonrpc_session_unlock__(waiter);
 775     }
 776 }
 777
 778 static void
 779 ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *waiter)
 780 {
 781     struct ovsdb_lock *lock = waiter->lock;
 782
 783     if (lock) {
 784         struct ovsdb_session *new_owner = ovsdb_lock_waiter_remove(waiter);
 785         if (new_owner) {
 786             ovsdb_jsonrpc_session_notify(new_owner, lock->name, "locked");
 787         } else {
 788             /* ovsdb_server_lock() might have freed 'lock'. */
 789         }
 790     }
 791
 792     ovsdb_lock_waiter_destroy(waiter);
 793 }
 794
 795 static struct jsonrpc_msg *
 796 ovsdb_jsonrpc_session_unlock(struct ovsdb_jsonrpc_session *s,
 797                              struct jsonrpc_msg *request)
 798 {
 799     struct ovsdb_lock_waiter *waiter;
 800     struct jsonrpc_msg *reply;
 801     struct ovsdb_error *error;
 802     const char *lock_name;
 803
 804     error = ovsdb_jsonrpc_session_parse_lock_name(request, &lock_name);
 805     if (error) {
 806         goto error;
 807     }
 808
 809     /* Report error if this session has not issued a "lock" or "steal" for this
 810      * lock. */
 811     waiter = ovsdb_session_get_lock_waiter(&s->up, lock_name);
 812     if (!waiter) {
 813         error = ovsdb_syntax_error(
 814             request->params, NULL, "\"unlock\" without \"lock\" or \"steal\"");
 815         goto error;
 816     }
 817
 818     ovsdb_jsonrpc_session_unlock__(waiter);
 819
 820     return jsonrpc_create_reply(json_object_create(), request->id);
 821
 822 error:
 823     reply = jsonrpc_create_error(ovsdb_error_to_json(error), request->id);
 824     ovsdb_error_destroy(error);
 825     return reply;
 826 }
 827
 828 static struct jsonrpc_msg *
 829 execute_transaction(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 830                     struct jsonrpc_msg *request)
 831 {
 832     ovsdb_jsonrpc_trigger_create(s, db, request->id, request->params);
 833     request->id = NULL;
 834     request->params = NULL;
 835     jsonrpc_msg_destroy(request);
 836     return NULL;
 837 }
 838
 839 static void
 840 ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s,
 841                                   struct jsonrpc_msg *request)
 842 {
 843     struct jsonrpc_msg *reply;
 844
 845     if (!strcmp(request->method, "transact")) {
 846         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 847         if (!reply) {
 848             reply = execute_transaction(s, db, request);
 849         }
 850     } else if (!strcmp(request->method, "monitor") ||
 851                (monitor2_enable__ && !strcmp(request->method, "monitor2"))) {
 852         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 853         if (!reply) {
 854             int l = strlen(request->method) - strlen("monitor");
 855             enum ovsdb_monitor_version version = l ? OVSDB_MONITOR_V2
 856                                                    : OVSDB_MONITOR_V1;
 857             reply = ovsdb_jsonrpc_monitor_create(s, db, request->params,
 858                                                  version, request->id);
 859         }
 860     } else if (!strcmp(request->method, "monitor_cancel")) {
 861         reply = ovsdb_jsonrpc_monitor_cancel(s, json_array(request->params),
 862                                              request->id);
 863     } else if (!strcmp(request->method, "get_schema")) {
 864         struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply);
 865         if (!reply) {
 866             reply = jsonrpc_create_reply(ovsdb_schema_to_json(db->schema),
 867                                          request->id);
 868         }
 869     } else if (!strcmp(request->method, "list_dbs")) {
 870         size_t n_dbs = shash_count(&s->up.server->dbs);
 871         struct shash_node *node;
 872         struct json **dbs;
 873         size_t i;
 874
 875         dbs = xmalloc(n_dbs * sizeof *dbs);
 876         i = 0;
 877         SHASH_FOR_EACH (node, &s->up.server->dbs) {
 878             dbs[i++] = json_string_create(node->name);
 879         }
 880         reply = jsonrpc_create_reply(json_array_create(dbs, n_dbs),
 881                                      request->id);
 882     } else if (!strcmp(request->method, "lock")) {
 883         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_WAIT);
 884     } else if (!strcmp(request->method, "steal")) {
 885         reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_STEAL);
 886     } else if (!strcmp(request->method, "unlock")) {
 887         reply = ovsdb_jsonrpc_session_unlock(s, request);
 888     } else if (!strcmp(request->method, "echo")) {
 889         reply = jsonrpc_create_reply(json_clone(request->params), request->id);
 890     } else {
 891         reply = jsonrpc_create_error(json_string_create("unknown method"),
 892                                      request->id);
 893     }
 894
 895     if (reply) {
 896         jsonrpc_msg_destroy(request);
 897         ovsdb_jsonrpc_session_send(s, reply);
 898     }
 899 }
 900
 901 static void
 902 execute_cancel(struct ovsdb_jsonrpc_session *s, struct jsonrpc_msg *request)
 903 {
 904     if (json_array(request->params)->n == 1) {
 905         struct ovsdb_jsonrpc_trigger *t;
 906         struct json *id;
 907
 908         id = request->params->u.array.elems[0];
 909         t = ovsdb_jsonrpc_trigger_find(s, id, json_hash(id, 0));
 910         if (t) {
 911             ovsdb_jsonrpc_trigger_complete(t);
 912         }
 913     }
 914 }
 915
 916 static void
 917 ovsdb_jsonrpc_session_got_notify(struct ovsdb_jsonrpc_session *s,
 918                                  struct jsonrpc_msg *request)
 919 {
 920     if (!strcmp(request->method, "cancel")) {
 921         execute_cancel(s, request);
 922     }
 923     jsonrpc_msg_destroy(request);
 924 }
 925
 926 static void
 927 ovsdb_jsonrpc_session_send(struct ovsdb_jsonrpc_session *s,
 928                            struct jsonrpc_msg *msg)
 929 {
 930     ovsdb_jsonrpc_monitor_flush_all(s);
 931     jsonrpc_session_send(s->js, msg);
 932 }
 933 \f
 934 /* JSON-RPC database server triggers.
 935  *
 936  * (Every transaction is treated as a trigger even if it doesn't actually have
 937  * any "wait" operations.) */
 938
 939 struct ovsdb_jsonrpc_trigger {
 940     struct ovsdb_trigger trigger;
 941     struct hmap_node hmap_node; /* In session's "triggers" hmap. */
 942     struct json *id;
 943 };
 944
 945 static void
 946 ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
 947                              struct json *id, struct json *params)
 948 {
 949     struct ovsdb_jsonrpc_trigger *t;
 950     size_t hash;
 951
 952     /* Check for duplicate ID. */
 953     hash = json_hash(id, 0);
 954     t = ovsdb_jsonrpc_trigger_find(s, id, hash);
 955     if (t) {
 956         struct jsonrpc_msg *msg;
 957
 958         msg = jsonrpc_create_error(json_string_create("duplicate request ID"),
 959                                    id);
 960         ovsdb_jsonrpc_session_send(s, msg);
 961         json_destroy(id);
 962         json_destroy(params);
 963         return;
 964     }
 965
 966     /* Insert into trigger table. */
 967     t = xmalloc(sizeof *t);
 968     ovsdb_trigger_init(&s->up, db, &t->trigger, params, time_msec());
 969     t->id = id;
 970     hmap_insert(&s->triggers, &t->hmap_node, hash);
 971
 972     /* Complete early if possible. */
 973     if (ovsdb_trigger_is_complete(&t->trigger)) {
 974         ovsdb_jsonrpc_trigger_complete(t);
 975     }
 976 }
 977
 978 static struct ovsdb_jsonrpc_trigger *
 979 ovsdb_jsonrpc_trigger_find(struct ovsdb_jsonrpc_session *s,
 980                            const struct json *id, size_t hash)
 981 {
 982     struct ovsdb_jsonrpc_trigger *t;
 983
 984     HMAP_FOR_EACH_WITH_HASH (t, hmap_node, hash, &s->triggers) {
 985         if (json_equal(t->id, id)) {
 986             return t;
 987         }
 988     }
 989
 990     return NULL;
 991 }
 992
 993 static void
 994 ovsdb_jsonrpc_trigger_complete(struct ovsdb_jsonrpc_trigger *t)
 995 {
 996     struct ovsdb_jsonrpc_session *s;
 997
 998     s = CONTAINER_OF(t->trigger.session, struct ovsdb_jsonrpc_session, up);
 999
1000     if (jsonrpc_session_is_connected(s->js)) {
1001         struct jsonrpc_msg *reply;
1002         struct json *result;
1003
1004         result = ovsdb_trigger_steal_result(&t->trigger);
1005         if (result) {
1006             reply = jsonrpc_create_reply(result, t->id);
1007         } else {
1008             reply = jsonrpc_create_error(json_string_create("canceled"),
1009                                          t->id);
1010         }
1011         ovsdb_jsonrpc_session_send(s, reply);
1012     }
1013
1014     json_destroy(t->id);
1015     ovsdb_trigger_destroy(&t->trigger);
1016     hmap_remove(&s->triggers, &t->hmap_node);
1017     free(t);
1018 }
1019
1020 static void
1021 ovsdb_jsonrpc_trigger_complete_all(struct ovsdb_jsonrpc_session *s)
1022 {
1023     struct ovsdb_jsonrpc_trigger *t, *next;
1024     HMAP_FOR_EACH_SAFE (t, next, hmap_node, &s->triggers) {
1025         ovsdb_jsonrpc_trigger_complete(t);
1026     }
1027 }
1028
1029 static void
1030 ovsdb_jsonrpc_trigger_complete_done(struct ovsdb_jsonrpc_session *s)
1031 {
1032     while (!list_is_empty(&s->up.completions)) {
1033         struct ovsdb_jsonrpc_trigger *t
1034             = CONTAINER_OF(s->up.completions.next,
1035                            struct ovsdb_jsonrpc_trigger, trigger.node);
1036         ovsdb_jsonrpc_trigger_complete(t);
1037     }
1038 }
1039 \f
1040 /* Jsonrpc front end monitor. */
1041 struct ovsdb_jsonrpc_monitor {
1042     struct ovsdb_jsonrpc_session *session;
1043     struct ovsdb *db;
1044     struct hmap_node node;      /* In ovsdb_jsonrpc_session's "monitors". */
1045     struct json *monitor_id;
1046     struct ovsdb_monitor *dbmon;
1047     uint64_t unflushed;         /* The first transaction that has not been
1048                                        flushed to the jsonrpc remote client. */
1049     enum ovsdb_monitor_version version;
1050 };
1051
1052 static struct ovsdb_jsonrpc_monitor *
1053 ovsdb_jsonrpc_monitor_find(struct ovsdb_jsonrpc_session *s,
1054                            const struct json *monitor_id)
1055 {
1056     struct ovsdb_jsonrpc_monitor *m;
1057
1058     HMAP_FOR_EACH_WITH_HASH (m, node, json_hash(monitor_id, 0), &s->monitors) {
1059         if (json_equal(m->monitor_id, monitor_id)) {
1060             return m;
1061         }
1062     }
1063
1064     return NULL;
1065 }
1066
1067 static bool
1068 parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value)
1069 {
1070     const struct json *json;
1071
1072     json = ovsdb_parser_member(parser, name, OP_BOOLEAN | OP_OPTIONAL);
1073     return json ? json_boolean(json) : default_value;
1074 }
1075
1076 static struct ovsdb_error * OVS_WARN_UNUSED_RESULT
1077 ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_monitor *dbmon,
1078                                     const struct ovsdb_table *table,
1079                                     const struct json *monitor_request,
1080                                     size_t *allocated_columns)
1081 {
1082     const struct ovsdb_table_schema *ts = table->schema;
1083     enum ovsdb_monitor_selection select;
1084     const struct json *columns, *select_json;
1085     struct ovsdb_parser parser;
1086     struct ovsdb_error *error;
1087
1088     ovsdb_parser_init(&parser, monitor_request, "table %s", ts->name);
1089     columns = ovsdb_parser_member(&parser, "columns", OP_ARRAY | OP_OPTIONAL);
1090     select_json = ovsdb_parser_member(&parser, "select",
1091                                       OP_OBJECT | OP_OPTIONAL);
1092     error = ovsdb_parser_finish(&parser);
1093     if (error) {
1094         return error;
1095     }
1096
1097     if (select_json) {
1098         select = 0;
1099         ovsdb_parser_init(&parser, select_json, "table %s select", ts->name);
1100         if (parse_bool(&parser, "initial", true)) {
1101             select |= OJMS_INITIAL;
1102         }
1103         if (parse_bool(&parser, "insert", true)) {
1104             select |= OJMS_INSERT;
1105         }
1106         if (parse_bool(&parser, "delete", true)) {
1107             select |= OJMS_DELETE;
1108         }
1109         if (parse_bool(&parser, "modify", true)) {
1110             select |= OJMS_MODIFY;
1111         }
1112         error = ovsdb_parser_finish(&parser);
1113         if (error) {
1114             return error;
1115         }
1116     } else {
1117         select = OJMS_INITIAL | OJMS_INSERT | OJMS_DELETE | OJMS_MODIFY;
1118     }
1119
1120     ovsdb_monitor_table_add_select(dbmon, table, select);
1121     if (columns) {
1122         size_t i;
1123
1124         if (columns->type != JSON_ARRAY) {
1125             return ovsdb_syntax_error(columns, NULL,
1126                                       "array of column names expected");
1127         }
1128
1129         for (i = 0; i < columns->u.array.n; i++) {
1130             const struct ovsdb_column *column;
1131             const char *s;
1132
1133             if (columns->u.array.elems[i]->type != JSON_STRING) {
1134                 return ovsdb_syntax_error(columns, NULL,
1135                                           "array of column names expected");
1136             }
1137
1138             s = columns->u.array.elems[i]->u.string;
1139             column = shash_find_data(&table->schema->columns, s);
1140             if (!column) {
1141                 return ovsdb_syntax_error(columns, NULL, "%s is not a valid "
1142                                           "column name", s);
1143             }
1144             ovsdb_monitor_add_column(dbmon, table, column, select,
1145                                      allocated_columns);
1146         }
1147     } else {
1148         struct shash_node *node;
1149
1150         SHASH_FOR_EACH (node, &ts->columns) {
1151             const struct ovsdb_column *column = node->data;
1152             if (column->index != OVSDB_COL_UUID) {
1153                 ovsdb_monitor_add_column(dbmon, table, column, select,
1154                                          allocated_columns);
1155             }
1156         }
1157     }
1158
1159     return NULL;
1160 }
1161
1162 static struct jsonrpc_msg *
1163 ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db,
1164                              struct json *params,
1165                              enum ovsdb_monitor_version version,
1166                              const struct json *request_id)
1167 {
1168     struct ovsdb_jsonrpc_monitor *m = NULL;
1169     struct ovsdb_monitor *dbmon = NULL;
1170     struct json *monitor_id, *monitor_requests;
1171     struct ovsdb_error *error = NULL;
1172     struct shash_node *node;
1173     struct json *json;
1174
1175     if (json_array(params)->n != 3) {
1176         error = ovsdb_syntax_error(params, NULL, "invalid parameters");
1177         goto error;
1178     }
1179     monitor_id = params->u.array.elems[1];
1180     monitor_requests = params->u.array.elems[2];
1181     if (monitor_requests->type != JSON_OBJECT) {
1182         error = ovsdb_syntax_error(monitor_requests, NULL,
1183                                    "monitor-requests must be object");
1184         goto error;
1185     }
1186
1187     if (ovsdb_jsonrpc_monitor_find(s, monitor_id)) {
1188         error = ovsdb_syntax_error(monitor_id, NULL, "duplicate monitor ID");
1189         goto error;
1190     }
1191
1192     m = xzalloc(sizeof *m);
1193     m->session = s;
1194     m->db = db;
1195     m->dbmon = ovsdb_monitor_create(db, m);
1196     m->unflushed = 0;
1197     m->version = version;
1198     hmap_insert(&s->monitors, &m->node, json_hash(monitor_id, 0));
1199     m->monitor_id = json_clone(monitor_id);
1200
1201     SHASH_FOR_EACH (node, json_object(monitor_requests)) {
1202         const struct ovsdb_table *table;
1203         const char *column_name;
1204         size_t allocated_columns;
1205         const struct json *mr_value;
1206         size_t i;
1207
1208         table = ovsdb_get_table(m->db, node->name);
1209         if (!table) {
1210             error = ovsdb_syntax_error(NULL, NULL,
1211                                        "no table named %s", node->name);
1212             goto error;
1213         }
1214
1215         ovsdb_monitor_add_table(m->dbmon, table);
1216
1217         /* Parse columns. */
1218         mr_value = node->data;
1219         allocated_columns = 0;
1220         if (mr_value->type == JSON_ARRAY) {
1221             const struct json_array *array = &mr_value->u.array;
1222
1223             for (i = 0; i < array->n; i++) {
1224                 error = ovsdb_jsonrpc_parse_monitor_request(
1225                     m->dbmon, table, array->elems[i], &allocated_columns);
1226                 if (error) {
1227                     goto error;
1228                 }
1229             }
1230         } else {
1231             error = ovsdb_jsonrpc_parse_monitor_request(
1232                 m->dbmon, table, mr_value, &allocated_columns);
1233             if (error) {
1234                 goto error;
1235             }
1236         }
1237
1238         column_name = ovsdb_monitor_table_check_duplicates(m->dbmon, table);
1239
1240         if (column_name) {
1241             error = ovsdb_syntax_error(mr_value, NULL, "column %s "
1242                                        "mentioned more than once",
1243                                         column_name);
1244             goto error;
1245         }
1246     }
1247
1248     dbmon = ovsdb_monitor_add(m->dbmon);
1249     if (dbmon != m->dbmon) {
1250         /* Found an exisiting dbmon, reuse the current one. */
1251         ovsdb_monitor_remove_jsonrpc_monitor(m->dbmon, m);
1252         ovsdb_monitor_add_jsonrpc_monitor(dbmon, m);
1253         m->dbmon = dbmon;
1254     }
1255
1256     ovsdb_monitor_get_initial(m->dbmon);
1257     json = ovsdb_jsonrpc_monitor_compose_update(m, true);
1258     json = json ? json : json_object_create();
1259     return jsonrpc_create_reply(json, request_id);
1260
1261 error:
1262     if (m) {
1263         ovsdb_jsonrpc_monitor_destroy(m);
1264     }
1265
1266     json = ovsdb_error_to_json(error);
1267     ovsdb_error_destroy(error);
1268     return jsonrpc_create_error(json, request_id);
1269 }
1270
1271 static struct jsonrpc_msg *
1272 ovsdb_jsonrpc_monitor_cancel(struct ovsdb_jsonrpc_session *s,
1273                              struct json_array *params,
1274                              const struct json *request_id)
1275 {
1276     if (params->n != 1) {
1277         return jsonrpc_create_error(json_string_create("invalid parameters"),
1278                                     request_id);
1279     } else {
1280         struct ovsdb_jsonrpc_monitor *m;
1281
1282         m = ovsdb_jsonrpc_monitor_find(s, params->elems[0]);
1283         if (!m) {
1284             return jsonrpc_create_error(json_string_create("unknown monitor"),
1285                                         request_id);
1286         } else {
1287             ovsdb_jsonrpc_monitor_destroy(m);
1288             return jsonrpc_create_reply(json_object_create(), request_id);
1289         }
1290     }
1291 }
1292
1293 static void
1294 ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *s)
1295 {
1296     struct ovsdb_jsonrpc_monitor *m, *next;
1297
1298     HMAP_FOR_EACH_SAFE (m, next, node, &s->monitors) {
1299         ovsdb_jsonrpc_monitor_destroy(m);
1300     }
1301 }
1302
1303 static struct json *
1304 ovsdb_jsonrpc_monitor_compose_update(struct ovsdb_jsonrpc_monitor *m,
1305                                      bool initial)
1306 {
1307     return ovsdb_monitor_get_update(m->dbmon, initial, &m->unflushed,
1308                                     m->version);
1309 }
1310
1311 static bool
1312 ovsdb_jsonrpc_monitor_needs_flush(struct ovsdb_jsonrpc_session *s)
1313 {
1314     struct ovsdb_jsonrpc_monitor *m;
1315
1316     HMAP_FOR_EACH (m, node, &s->monitors) {
1317         if (ovsdb_monitor_needs_flush(m->dbmon, m->unflushed)) {
1318             return true;
1319         }
1320     }
1321
1322     return false;
1323 }
1324
1325 void
1326 ovsdb_jsonrpc_monitor_destroy(struct ovsdb_jsonrpc_monitor *m)
1327 {
1328     json_destroy(m->monitor_id);
1329     hmap_remove(&m->session->monitors, &m->node);
1330     ovsdb_monitor_remove_jsonrpc_monitor(m->dbmon, m);
1331     free(m);
1332 }
1333
1334 static struct jsonrpc_msg *
1335 ovsdb_jsonrpc_create_notify(const struct ovsdb_jsonrpc_monitor *m,
1336                             struct json *params)
1337 {
1338     const char *method;
1339
1340     switch(m->version) {
1341     case OVSDB_MONITOR_V1:
1342         method = "update";
1343         break;
1344     case OVSDB_MONITOR_V2:
1345         method = "update2";
1346         break;
1347     case OVSDB_MONITOR_VERSION_MAX:
1348     default:
1349         OVS_NOT_REACHED();
1350     }
1351
1352     return jsonrpc_create_notify(method, params);
1353 }
1354
1355 static void
1356 ovsdb_jsonrpc_monitor_flush_all(struct ovsdb_jsonrpc_session *s)
1357 {
1358     struct ovsdb_jsonrpc_monitor *m;
1359
1360     HMAP_FOR_EACH (m, node, &s->monitors) {
1361         struct json *json;
1362
1363         json = ovsdb_jsonrpc_monitor_compose_update(m, false);
1364         if (json) {
1365             struct jsonrpc_msg *msg;
1366             struct json *params;
1367
1368             params = json_array_create_2(json_clone(m->monitor_id), json);
1369             msg = ovsdb_jsonrpc_create_notify(m, params);
1370             jsonrpc_session_send(s->js, msg);
1371         }
1372     }
1373 }
1374
1375 void
1376 ovsdb_jsonrpc_disable_monitor2(void)
1377 {
1378     /* Once disabled, it is not possible to re-enable it. */
1379     monitor2_enable__ = false;
1380 }